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排序方式: 共有270条查询结果,搜索用时 31 毫秒
71.
First-lactation milk yield test-day records on cows from Australia, Canada, Italy, and New Zealand were analyzed by single- and multiple-country random regression models. Models included fixed effects of herd-test day and breed composition-age at calving-season of calving by days in milk, and random regressions with Legendre polynomials of order four for animal genetic and permanent environmental effects. Milk yields in different countries were defined as genetically different traits for the purpose of multiple-trait model. Estimated breeding values of bulls and cows from single- and multiple-trait models were compared within and across countries for two traits: total milk yield in lactation and lactation persistency, defined as the linear coefficient of animal genetic curve. Correlations between single- and multiple-trait evaluations within country for total yield were higher than 0.95 for bulls and close to 1 for cows. Correlations for lactation persistency were lower than respective correlations for total yield. Between country correlations for lactation yield ranged from 0.93 to 0.96, indicating different ranking of bulls on different country scales under multiple-trait model. Lactation persistency had in general lower between-country correlations, with the highest values for Canada-Italy and Australia-New Zealand pairs, for both single- and multiple-country models. Although multiple-country random regression test-day model was computationally feasible for four countries, the same would not be true for routine international genetic evaluation in the near future. 相似文献
72.
Pattern Databases 总被引:1,自引:0,他引:1
The efficiency of A* searching depends on the quality of the lower bound estimates of the solution cost. Pattern databases enumerate all possible subgoals required by any solution, subject to constraints on the subgoal size. Each subgoal in the database provides a tight lower bound on the cost of achieving it. For a given state in the search space, all possible subgoals are looked up in the pattern database, with the maximum cost over all lookups being the lower bound. For sliding tile puzzles, the database enumerates all possible patterns containing N tiles and, for each one, contains a lower bound on the distance to correctly move all N tiles into their correct final location. For the 15-Puzzle, iterative-deepening A* with pattern databases(N ="8) reduces the total number of nodes searched on a standard problem set of 100 positions by over 1000‐fold. 相似文献
73.
Blake A. Schaeffer John Iiames John Dwyer Erin Urquhart Wilson Salls Jennifer Rover 《International journal of remote sensing》2013,34(22):7789-7805
ABSTRACTThe United States Harmful Algal Bloom and Hypoxia Research Control Act of 2014 identified the need for forecasting and monitoring harmful algal blooms (HAB) in lakes, reservoirs, and estuaries across the nation. Temperature is a driver in HAB forecasting models that affects both HAB growth rates and toxin production. Therefore, temperature data derived from the U.S. Geological Survey Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus thermal band products were validated across 35 lakes and reservoirs, and 24 estuaries. In situ data from the Water Quality Portal (WQP) were used for validation. The WQP serves data collected by state, federal, and tribal groups. Discrete in situ temperature data included measurements at 11,910 U.S. lakes and reservoirs from 1980 through 2015. Landsat temperature measurements could include 170,240 lakes and reservoirs once an operational product is achieved. The Landsat-derived temperature mean absolute error was 1.34°C in lake pixels >180 m from land, 4.89°C at the land-water boundary, and 1.11°C in estuaries based on comparison against discrete surface in situ measurements. This is the first study to quantify Landsat resolvable U.S. lakes and reservoirs, and large-scale validation of an operational satellite provisional temperature climate data record algorithm. Due to the high performance of open water pixels, Landsat satellite data may supplement traditional in situ sampling by providing data for most U.S. lakes, reservoirs, and estuaries over consistent seasonal intervals (even with cloud cover) for an extended period of record of more than 35 years. 相似文献
74.
Dai J.J. Di Xiao Shokooh F. Schaeffer C. Benge A. 《Industry Applications, IEEE Transactions on》2004,40(5):1191-1199
This paper reports the implementation of synchronous generator, induction machine, hydro turbine, and governor system, and excitation and automatic voltage regulator system models for transient stability study. These models are frequency dependent and are suitable for system transient studies involving drastic frequency changes, including generator startup and emergency load startup. A computer simulation program has been developed using these models for a transient stability study. The developed program is further validated and verified using real system testing data that includes the cases of generator startup and full-load shed in a nuclear power generation plant. Validation results show overall an excellent correlation between the computer simulation and the field-testing data. As a result, the program has been accepted by the plant for system modeling and emergency generator startup simulation studies. 相似文献
75.
Uzi Zahavi Ariel Felner Robert C. Holte Jonathan Schaeffer 《Artificial Intelligence》2008,172(4-5):514-540
Geometrical symmetries are commonly exploited to improve the efficiency of search algorithms. A new type of symmetry in permutation state spaces, duality, is introduced. Each state has a dual state. Both states share important attributes such as their distance to the goal. Given a state S, it is shown that an admissible heuristic of the dual state of S is an admissible heuristic for S. This provides opportunities for additional heuristic evaluations. An exact definition of the class of problems where duality exists is provided. A new search algorithm, dual search, is presented which switches between the original state and the dual state when it seems likely that the switch will improve the chance of reaching the goal faster. The decision of when to switch is very important and several policies for doing this are investigated. Experimental results show significant improvements for a number of applications, for using the dual state's heuristic evaluation and/or dual search. 相似文献
76.
The growth of commercial and academic interest in parallel and distributed computing during the past 15 years has been accompanied by a corresponding increase in the number of available parallel programming systems (PPS). However, little work has been done to evaluate their usability, or to develop criteria for such evaluations. As a result, the usability of a typical PPS is based on how easily a small set of trivially parallel algorithms can be implemented by its authors. The paper discusses the design and results of an experiment to compare objectively the usability of two PPS. Half of the students in a graduate parallel and distributed computing course solved a problem using the Enterprise PPS while the other half used a PVM-like library of message-passing routines. The objective was to measure usability. The experiment provided valuable feedback as to what features of PPS are useful and the benefits they provide during the development of parallel programs. Although many usability experiments have been conducted for sequential programming languages and environments, they are rare in the parallel programming domain. Such experiments are necessary to help narrow the gap between what parallel programmers want and what current PPSs provide. 相似文献
77.
Vandooren A. Barr A. Mathew L. White T.R. Egley S. Pham D. Zavala M. Samavedam S. Schaeffer J. Conner J. Nguyen B.-Y. White B.E. Jr. Orlowski M.K. Mogab J. 《Electron Device Letters, IEEE》2003,24(5):342-344
We report for the first time the performance of ultrathin film fully-depleted (FD) silicon-on-insulator (SOI) CMOS transistors using HfO/sub 2/ gate dielectric and TaSiN gate material. The transistors feature 100-150 /spl Aring/ silicon film thickness and selective epitaxial silicon growth in the source/drain extension regions. TaSiN-gate shows good threshold voltage control using an undoped channel, which reduces threshold voltage variation with silicon film thickness and discrete, random dopant placement. Device processing for CMOS fabrication is drastically simplified by the use of the same gate material for both n- and p-MOSFETs. Electrical characterization results illustrate the combined impact of using high-k dielectric and metal gate on the performance of ultrathin film FD SOI devices. 相似文献
78.
KL Campbell GL Czarnecki-Maulden DJ Schaeffer 《Canadian Metallurgical Quarterly》1995,56(11):1465-1469
Growing dogs were fed diets containing soy oil or poultry fat as the main fat source and soybean meal or meat meal as the main protein source to examine the effects of types of dietary fat and protein on fatty acid concentrations in serum and skin and on serum cholesterol concentrations. Dogs fed diets containing soy oil had higher serum linoleic acid concentrations and lower serum oleic acid, arachidonic acid, and cholesterol concentrations than dogs fed diets containing poultry fat. The type of dietary protein had marginal effects on fatty acid concentrations and did not affect serum cholesterol. Similar differences were found in cutaneous fatty acid concentrations, with soy oil-fed dogs having significantly (P < 0.05) higher linoleic acid and lower oleic acid concentrations in their skin than had poultry fat-fed dogs. This study suggested that dietary fat source influences serum and cutaneous fatty acid concentrations and serum cholesterol concentrations in dogs, irrespective of dietary protein source. 相似文献
79.
Elliot W. Jackson Jonathan P. Doubek Jeffrey S. Schaeffer John T. Lehman 《Journal of Great Lakes research》2013
Reported population biomass of Limnocalanus macrurus in Lake Huron has been underestimated by several-fold owing to application of an inappropriate length–weight regression model. During August and September the underestimates can exceed three-fold, suggesting that secondary production of the species in the lake is greater than previously thought. Increased representation of the species in the plankton community in recent years is associated with a decrease in its trophic level deduced through nitrogen stable isotope analysis of specimens from opportunistic samples obtained in 1993, 1995, and 2009. Limnocalanus15N enrichment relative to primary herbivores appears to have decreased by 1.5‰ over this time period. Similarly, Diaptomus15N enrichment relative to primary herbivores appeared to decrease by 1.1‰ from 1993 to 2009. Our data offer at least two possible explanations for this shift. (1) Limnocalanus has adopted a more herbivorous diet in response to the ecological changes in Lake Huron or (2) hypolimnetic Diaptomus have adopted a more herbivorous diet and Limnocalanus is relying in part on Diaptomus as a food source. 相似文献
80.
In a search for maximally valid indicators of academic departmental quality, 17 measures tapping 6 dimensions were examined in a multitrait multimethod manner with regard to their psychometric and other properties. Citations and graduates placed provided the best index of departmental quality. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献